Older children, younger children, and contemporaries all have their uses, but the uses of older and younger children, for the reasons just given, are mainly confined to the family. The great use of older children is to provide attainable ambitions. A child will make tremendous efforts to be thought worthy of joining in an older child’s game. The older child behaves in an offhand natural way, without the consideration and make-believe which is bound to form part of a grown-up person’s games with children. The same lack of consideration in a grown-up would be painful, both because the grown-up has power and authority, and because he plays to please the child, not to please himself. A child will be cheerfully submissive to an older brother or sister, in a way which would be impossible towards an adult except as a result of excessive discipline. The lesson of co-operation in a subordinate role is best learnt from other children; when grown-ups try to teach it, they are faced with the opposite dangers of unkindness and pretence--unkindness if they demand real co-operation, pretence if they are content with the appearance of it. I do not mean that either real or pretence co-operation is to be always avoided, but that it has not the spontaneity which is possible between an older and a younger child, and therefore cannot be combined for hours on end with pleasure to both parties. All through youth, slightly older people continue to have a special use in teaching--not formal teaching, but the sort which occurs outside working hours. A slightly older boy or girl remains always a very effective stimulus to ambition, and, if kind, can explain difficulties better than an adult, from the recent recollection of overcoming them. Even at the university, I learnt much from people a few years senior to me, which I could not have learnt from grave and reverend signors. I believe this experience is general wherever the social life of the university is not too rigidly stratified by “years”. It is, of course, impossible where, as too often happens, the older students consider it _infra dig_ to have anything to do with the younger ones.